OFFSET
1,6
LINKS
MATHEMATICA
a[n_] := GCD[DivisorSigma[1, n], n/2^IntegerExponent[n, 2]]; Array[a, 100] (* Amiram Eldar, Jul 22 2022 *)
PROG
(PARI)
A000265(n) = (n>>valuation(n, 2));
(Python)
from math import gcd
from sympy import divisor_sigma
def A355931(n): return gcd(divisor_sigma(n), n>>(~n&n-1).bit_length()) # Chai Wah Wu, Jul 22 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Antti Karttunen, Jul 22 2022
STATUS
approved